Brush-holder.



J. S. DEAN. BRUSH HOLDER. APPLICATION FILED lAN.4. i916.

Patented Mar. 4,1919.

INYENTOR ATTORNEY UNITED srarns PATENT orrrcn- JOHN S. DEAN, OI WILKINSBURG, PENNSYLVANIA, ASSIGNOR T0 WESTINGHOUE ELECTRIC AND 'MANUFACTURING COMPANY, A. CORPORATION OF PENNSYLVANIA.

BRUSH-HOLDER.

Specification of Letters Patent.

Patented Mar. 4, 19119.

1 Application filed January 4, 191.6. Serial No. 70,236.

To all whom it may concern:

Be it known that I, JOHN S. DEAN, a citizen of the United States, and a resident of lVilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and usefiul Improvement in Brush- Holders, of which the following is a specification.

Myinvention relates to brush holders for dynamo-electric machines and particularly to brush holders in which a flexible conductor or shunt is attached to the pressureexerting device that engages the currentcollecting brush, in order to limit the amount of current flowing through the resilient member of the pressure-exerting device.

The object of my invention is to provide. means for preventing the flexible conductor or shunt from coming into contact with portions of the brush holder body, whereby the conductor might lie injured.

In the accompanying drawings, Figure 1 is a view, partially in section and partially in side elevation of a brush holder embodying my invention; Fig.2 is a view, partially in section and partially in side elevation,

' showing my invention as applied to a differem type of brush holder from that shown in Fig. 1, and Fig. 3 is a fragmentary View showing a modification of my invention.

The brush holder general y comprises a main body member 1 that is provided, at one end, with a brush box 2 and is adapted to be mounted in any suitable manner by means of upwardly extending portions 3'. A current-collecting niember or brush a 'is adapted to slide within the brush box 2 and is held in operative relation to a coacting rotatable member of a dynamo-electric machine (\not shown) by means of a pressureexerting device 5. The pressure-exerting device 5 comprises a resilient member 6 that is carried by arotatably mounted arm 7. The arm 7 is mounted on a pin 8 carried by the body member 1 and tcnds'to rotate in a clockwise direction through the action of a coil spring 9, the force exerted by the spring being controlled by a ratchet and awl mechanism in a well known manner. lhe pressure-exerting device 5 further comprises a contact tip 10, preferably formed of a metal havlng a high electrical conductivity-and a flexible I conductor'or-shunt 11. The conductor 11 18 secured, at one end, intermediate theresilient member 6 and the contact tip 10 and, at the other end, to the portion of the body memher 1, as indicated at 12. The members 6, 10 and 11 are secured together in any suitable manner, such, for example, as by soldering or welding. The resilient member 6 is provided with a bent-over portion13 whichextends beyond the ends of the conductor 11 and the contact tip 10.

The side walls 14 and 15 of the brush box 2 are provided with notches 16 and 17 of substantially equal depth which are so positioned that the pressure exerting device 5 is permitted to enter the brush box 2 as the brush 4 wears down. The bent-over portion 13 is adapted to engage the bottom of the right-hand notch 17 before the portion of the conductor 11 adjacent to the contact ti 10 engages the bottom of the left-hand note 16. Thus, the bent-over portion 13 will prevent the flexible conductor ll'from coming into contact withthe bottom of the slot 17 if the brush 4: Wears down to such an extent as would otherwise permit such contact. The pressure-exerting device is further provided with a finger 18 by means of which the device 5 may be raised out of engagement with the brush 4 in order to permit its removal In case the brush 4; has been removed and the device 5 is allowed to snap downwardly under the action of the spring 9, the bentover portion 13 will prevent damage to the flexible conductor 11, as will be readily understood.

The brush holder-shown in Fig. 2 is of the same general construction as that shown in Fig. 1, with the exception that only the left-hand side wall 14 is provided with a notch 16. The finger 18 of the pressure-exerting device 5 is provided with a bent-over portion 19 that is adapted to engage the top of the wall 15 of the brush box 2 before the I portion of the flexible conductor 11 adjacent to the contact tip 10 engages the bottom, of the slot 16. The flexible conductor 11 will thus be protected from injury in the manner described with reference to Fig. 1.

In the modification shown in Fig. 3,-a plate 20 is interposed between the contact tip 10 and the flexible conductor 11 to engage the bottom of the slot 16 and thereby prevent injury to the conductor 11. The plate 20 is preferably formed from material of high electrical conductivity and possessing considerable mechanical strength, such as an alloy of copper andnickel.

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